Chemical Composition and Aging Characteristics of Linear SBS Modified Asphalt Binders

摘要

Atomic force microscopy-based infrared spectroscopy (AFM-IR) is an advanced technology derived from two existing technologies. Recently, AFM-IR has been applied to perform the unambiguous chemical analysis of the material with the spatial resolution of the AFM. This study aimed to collect topography images, AFM-IR chemical images at 966 cm(-1), and AFM-IR infrared spectra of one-plant-manufactured linear styrene-butadiene-styrene (SBS) modified asphalt binder before and after aging using AFM-IR. Analyses of topography images indicated that the addition of linear SBS modifiers enriched the microstructure of the asphalt binder surface and that the degradation of linear SBS modifiers reduced the surface roughness. Furthermore, the polybutadiene (PB) groups showed a uniform distribution on the linear SBS modified asphalt binder surface before aging, while the PB content of different phases began to deviate after aging. Based on the quantitative analysis methods of AFM-IR infrared spectra, calculated PB indices decreased, while carbonyl indices increased. The changing trend of the resultant PB and carbonyl indices of linear SBS modified asphalt binders measured by AFM-IR before and after aging was consistent with that measured by Fourier-transform infrared spectroscopy (FT-IR). Further research demonstrated that the bee structures consisted of linear SBS modifiers and other base asphalt binder composition besides waxes. Additionally, base asphalt binders rather than SBS modifiers led to the chemical composition difference between the surface and the bulk of this linear SBS modified asphalt binder.